PolyTest.java

import org.checkerframework.checker.fenum.qual.FenumBottom;
import org.checkerframework.checker.fenum.qual.PolyFenum;
import org.checkerframework.checker.fenum.qual.SwingCompassDirection;

public class PolyTest {
    public static boolean flag = false;

    @PolyFenum String merge(
            @PolyFenum String a,
            @PolyFenum String b,
            @SwingCompassDirection String x,
            @FenumBottom String bot) {
        // Test lub with poly and a qualifier that isn't top or bottom.
        String y = flag ? a : x;
        //:: error: (assignment.type.incompatible)
        @PolyFenum String y2 = flag ? a : x;

        // Test lub with poly and bottom.
        // Test lub with poly and bottom.
        @PolyFenum String z = flag ? a : bot;

        // Test lub with two polys
        return flag ? a : b;
    }
}